Malicious PDF — malware analysis report

Static analysis result for SHA-256 4d94b9f8d28586c8…

MALICIOUS

PDF

83.1 KB Created: 2021-08-01 04:37:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 7c03f12052fa1686a6728474a0d1b93f SHA-1: 5f4d0354dfc06ccbcf5755271df38595ee6a7893 SHA-256: 4d94b9f8d28586c8435698e8dc79d1c591b3f23d04327da4bd7c914061f8c629
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous links, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, indicating it's not intended for direct user reading but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://sanvexe.vn/webroot/img/files/8754081276.pdf
    • http://timavoshipsupply.it/userfiles/file/lezujavapufo.pdf
    • https://tamtam.com.ua/wp-content/plugins/super-forms/uploads/php/files/80c0197c0f39d0d224b861b8b4ff0d59/6594612087.pdf
    • http://bjoybrands.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e5db346ff58---bazuruxefafigevaponi.pdf
    • http://apsons.eu/files/file/sezet.pdf
    • http://cageart.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16090e554e06f1---paketirogekazebij.pdf
    • https://themodernla.com/wp-content/plugins/super-forms/uploads/php/files/dfd88cc0c0f3095e7f367adb598a9af2/mesirexufewem.pdf
    • http://sns.hu/_user/file/zodaperokarogiwalabiruw.pdf
    • https://mudrun.com/home/mud/public_html/ckfinder/userfiles/files/vuravasilinef.pdf
    • https://njsolarpower.com/wp-content/plugins/super-forms/uploads/php/files/3127d99d24b82cbe515db007c95af1d2/27790154488.pdf
    • http://serendipityorlando.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609000e424fe9---13366659702.pdf
    • http://sixtyguildersresearch.com/admin/photos/file/22222770918.pdf
    • http://modelkyujin.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f43536e3f5b---xebex.pdf
    • https://jgmurphy.com/wp-content/plugins/super-forms/uploads/php/files/f1be484c43434f41ad2f572e7482c262/xelogikigixunarevefonojed.pdf
    • https://www.hungryalex.com/wp-content/plugins/super-forms/uploads/php/files/754f3eacf7ce4cde086a2da776727ec5/wokarimomudo.pdf
    • https://ballestermultiservicios.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a8707c2a80f---fuwoz.pdf
    • http://rutherford58.com/clients/5/5b/5b2824e44de76337c32dfcbc3ee6dba3/File/legatozetopemutob.pdf
    • https://www.techsrollout.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610091dbd57d0---83916851825.pdf
    • http://eurogeographyjournal.eu/admin/fckfiles/file/giliwabopiwosuxom.pdf
    • https://www.auditek.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1606f18b3f38b7---43233992764.pdf
    • https://cor.org.ar/wp-content/plugins/super-forms/uploads/php/files/9r5vjdcidhnjoqom1dp5m40nm0/73002987233.pdf
    • http://evabody.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1609002ad0e001---kewilalarobibi.pdf
    • https://maloneslandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609be487e2f82---71933700963.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=relative+clauses+worksheet+year+6
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000df9d.bin
8c27de560c5a35685be3f789491c72417fcdbe3500bf5527cc4da3a9a327167f
pdf-font-stream PDF embedded font (sfnt) at offset 0xDF9D 17204 bytes
font_01_sfnt_off00010ce4.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x10CE4 16792 bytes
font_02_sfnt_off000124fb.bin
93d24acabcf58e742cb8a1db5595d243c286a8597b2faf69528e5f3d79838f4a
pdf-font-stream PDF embedded font (sfnt) at offset 0x124FB 10892 bytes